Patents Assigned to Hofmann Maschinenbau GmbH
  • Patent number: 5705748
    Abstract: In a method and apparatus for determining the rotary angular position of a rotary member when measuring unbalance on the rotary member, during an unbalance measuring run the rotary member is twice sensed in the peripheral direction in a given succession in respect of time, resulting in the formation of first and second angle signals which are displaced in respect of time. The two signals are stored, having regard to their spacing in respect of time. The two signals are evaluated for rotating the rotary member, in dependence on the measured angular position of an unbalance, into a balancing position for carrying out a balancing operation on the rotary member.
    Type: Grant
    Filed: August 31, 1994
    Date of Patent: January 6, 1998
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Uwe Moench
  • Patent number: 5600062
    Abstract: An apparatus for unbalance measurement on a rotary member comprising a rotary mounting device for the rotary member and an oscillatable support for the rotary mounting device for supporting same on the foundation of the apparatus. A force and/or oscillation measuring equipment is operatively disposed between the foundation and the rotary mounting device for measuring centrifugal forces and/or oscillations which result from unbalance of the rotary member. To determine the mass of the rotary member in the rotary mounting device, the apparatus measures the force due to the weight of the rotary member, disposed in the path of transmission of force between the rotary mounting device and the foundation.
    Type: Grant
    Filed: December 8, 1994
    Date of Patent: February 4, 1997
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Uwe Moench
  • Patent number: 5481912
    Abstract: A method and apparatus for dynamically balancing a rotary member by mass compensation in first and second correction planes on the rotary member, wherein in dependence on the rotary member mass, its mass moment of inertia, the measuring speed of rotation and the spacing of the correction planes from the measuring planes, measurement value vectors which are supplied by measuring sensors in the measuring planes are turned through angles which are obtained from a respective stored family of curves produced by means of test runs. Each family of curves represents phase shifts of the measurement vectors relative to the correction vectors in the correction planes in dependence on the rotary member mass, the mass moment of inertia, the speed of measuring rotation and the spacing of the rotary member or the correction plane from the measuring plane.
    Type: Grant
    Filed: December 3, 1993
    Date of Patent: January 9, 1996
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Gunther Himmler
  • Patent number: 5467647
    Abstract: An apparatus for mounting a pneumatic tire in a testing and/or measuring apparatus comprises first and second mounting rim portions for holding a pneumatic tire between them in an inflated condition, on a rotatable spindle. The mounting rim portions are carried in concentric relationship with respect to the axis of rotation of the spindle, the first mounting rim portion being slidable in the axial direction on a guide. A clamp non-rotatably clamps the first rim portion to the guide along which the rim portion is displaceable in a released condition. The clamp includes a clamping element which is disposed about the axis and which is deformable upon inflation of the tire by the tire-inflation pressure to form a positively locking engagement between the first rim portion and the guide.
    Type: Grant
    Filed: May 25, 1994
    Date of Patent: November 21, 1995
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Michael Schepp
  • Patent number: 5467653
    Abstract: An apparatus for unbalanced compensation of a grinding wheel which is rotatable about an axis of rotation, with compensating weights which are guided rotatably about the axis of rotation of the grinding wheel with symmetrical mass distribution relative to a central plane of the grinding wheel which is perpendicular to the axis of rotation. A positioning mechanism is provided for different angular positionings of the compensating weights. The compensating weights are mounted for rotation through 360.degree. about the axis of rotation at different radii, the product of the mass of each compensating weight and its associated radius being equal to the product of the mass of each other compensating weight and its associated radius.
    Type: Grant
    Filed: May 24, 1993
    Date of Patent: November 21, 1995
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Eugen Lulay
  • Patent number: 5423217
    Abstract: A measuring apparatus for measuring forces which occur when a rotary body is clamped on a testing machine drive shaft include a face clamping force measuring means for measuring face clamping forces acting between said rotary body and a clamping element contact face which is disposed perpendicularly to the axis of the rotary body, and/or a radial clamping force measuring means for measuring a radial clamping force acting between said rotary body and a radially outwardly acting clamping means.
    Type: Grant
    Filed: July 26, 1993
    Date of Patent: June 13, 1995
    Assignee: Hofmann Maschinenbau GmbH
    Inventors: Gunther Himmler, Werner Bickelhaupt
  • Patent number: 5421197
    Abstract: A method of measuring irregularities of a pneumatic tire comprises carrying out first and second measuring runs, each of which involves rolling the tire in an inflated condition in a rotary mounting means under a given preload against a test surface and measuring the reaction forces which occur in that operation in the form of two force fluctuation diagrams. The tire is turned, for example, through 120.degree. or 180.degree. about the axis of the rotary mounting means between the measuring runs and a correction value is ascertained from the two force fluctuation diagrams to compensate for error values resulting from the rotary mounting means.
    Type: Grant
    Filed: November 12, 1993
    Date of Patent: June 6, 1995
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Klaus-Peter Ohms
  • Patent number: 5421199
    Abstract: A method of unbalance measurement of a rotary member for balancing thereof in first and second compensating planes includes the steps of: performing test runs wherein the rotary member is rotated about is axis with test weights on the rotary member rotating in different planes thereof, the planes being perpendicular to the axis of rotation of the rotary member, and in each test run the effects of centrifugal forces produced by the test weights are measured simultaneously in more than two measuring planes which differ from the planes in which the test weights rotate so as to provide correlation coefficient matrices in the respective measuring planes; evaluating all of the determinants associated with a given type of rotary member; and ascertaining unbalance vectors of a rotary member of a given type in the respective measuring planes by use of the measuring planes which are determined by the correlation coefficient matrix whose determinant is greatest for that type of rotary member.
    Type: Grant
    Filed: July 9, 1992
    Date of Patent: June 6, 1995
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Gunther Himmler
  • Patent number: 5359885
    Abstract: A method of measuring radial and/or lateral run-out of a rotary member, where the rotary member is mounted in a testing machine by a play-compensating clamping arrangement, and rotated. While it rotates the rotary member is sensed in the region of its peripheral and/or lateral surfaces and the result of the sensing operation is used to produce run-out diagrams. First and second run-out diagrams which are turned relative to each other through 180.degree. with respect to the clamping mounting arrangement are combined together, thereby to compensate in the combination diagram for the geometrical measurement errors resulting from the clamping mounting arrangement in the initial diagrams.
    Type: Grant
    Filed: April 1, 1993
    Date of Patent: November 1, 1994
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Klaus-Peter Ohms
  • Patent number: 5267380
    Abstract: In a method and apparatus for centering a rotary body such as a motor vehicle tire the rotary body is put into a centered position by means of a plurality of centering means which engage the circular periphery of the rotary body at distributed positions around the periphery thereof and which are acted upon by a centering force. The centering force acting on the centering means is set to be proportional to the diameter of the rotary body.
    Type: Grant
    Filed: February 1, 1991
    Date of Patent: December 7, 1993
    Assignee: Hofmann Maschinenbau GmbH
    Inventors: Heinz Ronge, Werner Lehr
  • Patent number: 5239867
    Abstract: In a method and apparatus for improving the fit of a pneumatic tire on a motor vehicle wheel rim, before a wheel balancing operation is carried out the wheel is accelerated to a maximum permissible peripheral speed and centrifugal force acting at the wheel is measured at that speed. The drive for the wheel with tire thereon is stopped when the measured variation in centrifugal force reaches or falls below a predetermined limit value.
    Type: Grant
    Filed: July 9, 1991
    Date of Patent: August 31, 1993
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Gunther Himmler
  • Patent number: 5222778
    Abstract: Apparatus for gripping a workpiece such as a rotor is provided which includes gripper arms, a pressure-sensitive sensing member on one of the arms for continuously measuring the gripping force applied by the arms, and a piezoelectric actuator on the outer arm which is actuated to provide fine adjustment of the gripping force in dependence on the output of the sensing member.
    Type: Grant
    Filed: September 23, 1991
    Date of Patent: June 29, 1993
    Assignee: Hofmann Maschinenbau GmbH
    Inventor: Uwe Moench
  • Patent number: 5222539
    Abstract: An apparatus for improving the fit of a pneumatic tire on a wheel comprises a plurality a conical pressure rollers. A first pair of pressure rollers with their larger diameter positioned downwardly are arranged diametrically opposite each other with respect to the axis of the tire. A second pair of pressure rollers with their larger diameter positioned upwardly are arranged similarly diametrically opposite the pressure rollers with their larger diameter upwardly are arranged alternately with pressure rollers with their larger diameter downwardly in the peripheral direction of the tire.
    Type: Grant
    Filed: June 4, 1991
    Date of Patent: June 29, 1993
    Assignee: Hofmann Maschinenbau GmbH
    Inventors: Franz Ruppert, Georg Lipponer
  • Patent number: 5197327
    Abstract: In a rotor wheel assembly for a tire testing drum comprising a hub and a testing drum portion which is supported relative to the hub by support means, the support means consists exclusively of discs, with at least three discs arranged symmetrically relative to a central plane passing radially through the hub. The support discs may comprise first and second conical discs and at least one flat disc.
    Type: Grant
    Filed: March 1, 1991
    Date of Patent: March 30, 1993
    Assignee: Hofmann Maschinenbau GmbH
    Inventors: Franz Ruppert, Joachim Schwab
  • Patent number: 5196772
    Abstract: Apparatus for fitting a motor vehicle tire on a disc wheel comprises a tire fitting tool mounted rotatably about an axis, an electric drive motor to drive the tire fitting tool about the axis, a current supply means for the drive motor, and a torque limiting means to terminate the rotary drive to the motor when a predetermined torque transmitted to the tire fitting tool is exceeded, thereby to protect the tire from overloading in the fitting operation.
    Type: Grant
    Filed: August 27, 1991
    Date of Patent: March 23, 1993
    Assignee: Hofmann Maschinenbau GmbH
    Inventors: Heinz Kupka, Heinz Ronge